Glutamic acid is an excitatory neurotransmitter most abundantly present in the central nervous system of mammals. Glutamic acid plays an important role in the cognition, mood and control of motor function, and the neurotransmission thereof becomes unstable in mental diseases and neuropathy. Glutamic acid receptors are classified into ion ligand-gated ion channel and G protein conjugated-type receptor, and the ligand-gated ion channel is further classified into α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor, N-methyl-D-aspartic acid (NMDA) receptor and kainic acid (KA) receptor. (non-patent document 1)
AMPA receptor is one kind of receptor for excitatory neurotransmitter glutamic acid, and was named based on selective activation of the receptor by AMPA. AMPA receptor consists of 4 subunits (GluR1, GluR2, GluR3, GluR4). Each subunit contains flip type and flop type splicing variants. In the living body, AMPA receptor forms a homogeneous or heterogeneous tetramer consisting of such subunits. It has been reported that the physiological property of AMPA receptor varies depending on the subunits constituting the receptor. (non-patent documents 1, 2, 3)
The importance of AMPA receptor in brain physiology is well known, and a compound having an AMPA receptor function enhancing action is expected to be useful as a drug for the prophylaxis or treatment of mental diseases, neurodegenerative disease, memory disorders, sleep disorder and the like. (non-patent documents 4, 5)
As a heterocyclic compound, patent document 1 discloses disodium {4-(acetylamino)-8-[(3-{2-[4-(acetylamino)-2,2-dioxido-7-(sulfonatomethyl)-6H-pyrazolo[5,1-c][1,2,4]thiadiazin-8-yl]ethenyl}-5,5-dimethylcyclohex-2-en-1-yl)methylidene]-2,2-dioxido-8H-pyrazolo[5,1-c][1,2,4]thiadiazin-7-yl}methanesulfonate.
In addition, non-patent document 6 discloses 2,2,2-trichloro-N-(7,7-diphenyl-6,7-dihydro-5H-pyrrolo[2,1-c][1,2,4]thiadiazol-3-ylidene)acetamide.